Rectilinear magazine

ABSTRACT

A small arms magazine has a rectilinear form and the arcuate segmental configuration of a stack of nested tapered cartridges is accommodated by a follower loaded by a biasing spring. The spring has a plurality of turns and at each turn a pair of opposed re-entrant portions freely engage opposed complementary internal ridges in opposed side walls of the magazine. The last half turn of the spring is raised at a greater angle than the other turns with the spring in a free state. When full, the follower is inclined at a maximum angle to the closed end of the magazine and this angle decreases progressively toward zero as the magazine is emptied.

United States Patent Bredbury Apr. 10, 1973 [54] RECTILINEAR MAGAZINE3,440,751 4/1969 Fremont ..42/50 Inventor: David 0- y, Christmas Hm3,619,929 1 H1971 Fremont ..42/50 Road Guflford Conn' 06437 PrimaryExaminerBenjamin A. Borchelt [22] Filed: Oct. 12, 1971 AssistantExaminerC. T. Jordan [21 1 App. NOJ 187,954 Att0rneyEdw1n E. GrelggRelated [1.8. Application Data ABSTRACT A small arms magazine has arectilinear form and the arcuate segmental configuration of a stack ofnested tapered cartridges is accommodated by a follower loaded by abiasing spring. The spring has a plurality of turns and at each turn apair of opposed re-entrant portions freely engage opposed complementaryinternal ridges in opposed side walls of the magazine. The last halfturn of the spring is raised at a greater angle than the other turnswith the spring in a free state. When full, the follower is inclined ata maximum angle to the closed end of the magazine and this angledecreases progressively toward zero as the magazine is emptied.

8 Claim, 4 Drawing Figures PATENTEDAPR 1 OISYS RECTILINEAR MAGAZINE Thisapplication is a continuation-in-part of application, Ser. No. 868,310,filed Oct. 22, I969, now abandoned.

BACKGROUND OF THE INVENTION Field of the Invention This inventionrelates to a small arms ammunition magazine.

SUMMARY OF THE INVENTION To accommodate the arcuate segmentalconfiguration of either a single or double stack of cartridges, each ofwhich tapers by approximately 1, it has hitherto been necessary toprovide magazines for small arms which are themselves segmental. By thisexpedient a steady pressure can be exerted by a spring acting through afollower and the cartridges are therefore delivered at the open end ofthe magazine correctly aligned with respect to the breech of theassociated small arm.

Clearly, the utilization of a magazine of rectilinear form throughoutits length is desirable, particularly from the manufacturing standpoint,but correct presentation of a delivered cartridge has not hitherto beenpossible with a magazine of rectilinear form. 7

It is an object of the present invention to provide a magazine for smallarms ammunition which is of rectilinear form, but which neverthelesspresents cartridges in succession at the open end of the magazine with asubstantially even pressure along the length thereof.

According to the present invention there is provided a small armsmagazine comprising an 1 elongate rectilinear casing having a pair ofopposed side walls each having at least a first elongate ridge, a baseplate, and means defining an opening at the opposite'end of the casingfrom the base plate for dispensing cartridges singly to the breech of asmall arm, an elongate spring having a plurality of turns each with twoportions, both of which are formed to cooperate slidingly with therespective said ridges of the said side walls, and a fol lower memberrigid with the end of the spring remote from the base plate, the saidportions of the turns of the spring and the ridges of the side wallsserving to guide the spring and to prevent the spring from slidingtoward the rear of the magazine (toward the butt of the weapon)irrespective of its actual length and thereby to accommodate tilting ofthe follower member from a maximum with the magazine filled to a minimumwith the magazine empty. Further, the last half turn of the spring israised at a greater angle than the other turns with the spring in a freestate to place additional pressure on the rear of the follower.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of a small arms magazinein accordance with the invention will now be described, by

way of example, with reference to the accompanying diagrammatic drawing,in which:

FIG. I is a side elevation of a magazine in accordance with theinvention;

FIG. 2 is a cross section on the line IIII of FIG. 1;

FIG. 3 is a fragmentary side elevation of the spring in its free state;and

FIG. 4 is a schematic view showing the different positions of thefollower at different conditions ofloading.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,the magazine 10 comprises a casing having a pair of opposed side wallsof rectangular form and each having three spacedlongitudinally-extending grooves ll, 12 and 13 and 11', 12 and 13',respectively. The grooves are each of approximately semi-circular crosssection, and the first grooves 11, 11', have a diameter equal toapproximately twice that of the second and third grooves 12, 12' and 13,13. The grooves 11, ll, 12, 12' and 13, 13 lie opposite one another inpairs respectively and, because the magazine is made of sheet metal andthe grooves are formed by a pressing operation, each one of the groovesis complemented by an internal ridge or rib l4, l4, l5, l5 and 16, 16'.

The first ridges I4, 14' corresponding to the first grooves serve asguides for a spring 17 of special form now to be described. The springis basically helical but the turns are each formed as shown in FIG. 2,that is, with two long rectilinear portions 18, 19 extending parallel tothe side walls 20, 21 of the magazine, two concave curved portions 22,23 extending from the rectilinear portions 18, 19 and two semi-circularportions 24, 25, one of which joins the two portions l8, l9 and theother of which joins the two portions 22, 23. The upper'one-half turn orterminal turn 26 of the spring has been extended and raised at a greaterangle than the other turns with the spring in a free state in order todeliver additional pressure to the rear of the follower when nearlyempty. As the cartridges are expended, the weight exerted on the frontof the follower is reduced as is the amount of aggregate taper. Thiswould normally lead to a nose-up condition for the last l0 cartridges.The additional one-half turn, however, removes the possibility ofexperiencing excessive pressure at the magazine front.

A follower 40 is secured to the top half turn or terminal turn of thespring and bears against the bottom of the stack of cartridges, one ofwhich is shown in dotted lines in FIG. 3.

As illustrated schematically in FIG. 4, the follower assumes differentpositions at different conditions of loading. In condition A thefollower 40 is shown in the position it assumes when spring 17 is in afree state. In this condition the follower 40 slopes forwardly anddownwardly at an angle of about 24 to the horizontal. In condition B thefollower is shown in the position when installed in the magazine, withthe magazine empty of cartridges. The follower 40 in this conditionbears against the conventional lips at the top of the magazine and ishorizontal or at to the vertical centerline 41. In condition C thefollower 40 is shown in the position it assumes with the magazine fullyloaded. In this condition the follower 40 slopes forwardly and upwardlyat an angle of about 15 to the horizontal.

Thus, as the cartridges are urged to the top of the magazine fordelivery from the open end the follower gradually changes from theposition of condition C to the position of condition B. However, sincein relaxed position the spring tends to slant the follower in theposition of condition A, it will be appreciated that at all times thefollower exerts more pressure on the rear of the cartridges than on thefront, thus preventing a noseup condition of the cartridges.

The by walls 20, 21 of the magazine are joined to one another by a frontwall 30 and a shaped rear wall 31. The rear wall 31 is formedsubstantially be two portions 32, 33, of crank-section, the portion 32having a smaller intermediate limb than the portion 33. One limb of eachcrank-section portion 32, 33 overlaps the corresponding limb of theother crank-section portion and these two limbs are joined togetheralong their lengths.

The magazine casing is completed by a base plate 34 and a contoured topportion 35 which has an opening for dispensing the cartridges one by oneinto the small arm in which the magazine is mounted. The opening is ofconventional form for small arms magazines and similarly the followermember which contacts the lowermost cartridge and is secured to thespring is of conventional form.

The grooves and complementary internal ridges provide the conventionreinforcing purpose, prevent excess friction with the cartridges and thefirst ridges 14, 14' act as guides for the spring throughout its lengthand irrespective of its degree of compression and prevent its slidingtoward the rear of the magazine or buckling.

It follows that the rectilinear form of the magazine casing enablesparticularly straightforward manufacturing techniques to be employed,especially with regard to the fabrication and joining operations andthat the spring form and cooperating ridges ensure correct feed of thearcuate stack of cartridges to the dispensing opening irrespective ofthe number of cartridges in the magazine. The joining operation can becarried out on an automatic welding machine.

The magazine can be employed with a stack made of a single row ofcartridges or, as a so-called high-capacity magazine with the stackformed by two rows of cartridges with those of one row staggered withrespect to the other row and thus partially interdigitating. The lattermagazine can carry 30 or more cartridges and is suitable for use withthe M-l6 rifle of the United States Army or any other small armutilizing a tapered cartridge.

That which is claimed is:

l. A small arms magazine comprising an elongate rectilinear casinghaving a pair of opposed side walls each having at least a firstelongate ridge,

a base plate, and

means defining an opening at the opposite end of the casing from thebase plate for dispensing cartridges singly therefrom,

an elongate spring having a plurality of turns with two portions formedtherein to cooperate slidingly with a respective ridge on each sidewall, and

a follower member rigid with the end of the spring remote from the baseplate,

the said portions of the turns of the spring and the ridges of the sidewalls serving to guide the spring irrespective of its actual length andthereby to accommodate tilting of the follower member from a maximumwith the magazine filled to a minimum with the magpzine empty. 2. Amagazine according to claim wherein said ridges are internal and saidspring portions are concave.

3. A magazine according to claim 1, wherein said first ridges lieopposite one another.

4. A magazine according to claim 1, wherein each side wall has secondand third rectilinear ridges.

5. A magazine according to claim 1, wherein each turn of the spring isof elongated form and includes a pair of opposed straight portions,

a pair of opposed concave portions each of which forms a continuation ofone of the straight portions, and

a pair of opposed semi-circular end portions, one of said end portionsserving to join the concave portions and the other of said end portionsserving to join the straight portions.

6. A magazine according to claim 1, wherein the spring exerts greaterpressure on the back of the follower than on the front.

7. A magazine according to claim 6 in which the upper terminal turn ofthe spring, when in its free state, is raised at a greater angle thanthe other turns in order to exert said greater pressure on the back ofthe follower.

8. A magazine according to claim 4, wherein said rectilinear ridges aredisposed internally of the magazine.

1. A small arms magazine comprising an elongate rectilinear casinghaving a pair of opposed side walls each having at least a firstelongate ridge, a base plate, and means defining an opening at theopposite end of the casing from the base plate for dispensing cartridgessingly therefrom, an elongate spring having a plurality of turns withtwo portions formed therein to cooperate slidingly with a respectiveridge on each side wall, and a follower member rigid with the end of thespring remote from the base plate, the said portions of the turns of thespring and the ridges of the side walls serving to guide the springirrespective of its actual length and thereby to accommodate tilting ofthe follower member from a maximum with the magazine filled to a minimumwith the magazine empty.
 2. A magazine according to claim 1, whereinsaid ridges are internal and said spring portions are concave.
 3. Amagazine according to claim 1, wherein said first ridges lie oppositeone another.
 4. A magazine according to claim 1, wherein each side wallhas second and third rectilinear ridges.
 5. A magazine according toclaim 1, wherein each turn of the spring is of elongated form andincludes a pair of opposed straight portions, a pair of opposed concaveportions each of which forms a continuation of one of the straightportions, and a pair of opposed semi-circular end portions, one of saidend portions serving to join the concave portions and the other of saidend portions serving to join the straight portions.
 6. A magazineaccording to claim 1, wherein the spring exerts greater pressure on theback of the follower than on the front.
 7. A magazine according to claim6 in which the upper terminal turn of the spring, when in its freestate, is raised at a greater angle than the other turns in order toexert said greater pressure on the back of the follower.
 8. A magazineaccording to claim 4, wherein said rectilinear ridges are disposedinternally of the magazine.